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In this article Xiaobian for you to introduce in detail "what are the elements of UML drawing tools", the content is detailed, the steps are clear, the details are handled properly, I hope that this article "what are the elements of UML drawing tools" can help you solve your doubts, the following follows the editor's ideas slowly in depth, together to learn new knowledge.

I. Overview

UnifiedModelingLanguage (UML), also known as Unified Modeling language or Standard Modeling language, is an OMG standard that began in 1997. It is a graphical language that supports modeling and software system development. It provides modeling and visualization support for all stages of software development, including requirements analysis, specifications, construction and configuration.

One of the most exciting parts of the development of object-oriented Analysis and Design (OOA&D,OOAD) methods emerged in the late 1980s and 1990s, and UML is the product of this most exciting part. It not only unifies the representation methods of Booch, Rumbaugh and Jacobson, but also makes further development, and finally unifies it into a standard modeling language accepted by the public.

Second, the content of the standard modeling language UML

First of all, UML integrates the basic concepts of Booch, OMT and OOSE methods, and most of these basic concepts are the same as those in other object-oriented technologies. Therefore, UML is bound to become a simple and consistent modeling language that users of these and other methods are happy to adopt. Secondly, UML is not only a simple confluence of the above methods, but also widely solicited opinions on the basis of these methods. UML expands the application scope of existing methods. Third, UML is a standard modeling language, not a standard development process. Although the application of UML must be based on the development process of the system, different development processes need to be adopted because of different organizations and different application fields.

As a modeling language, the definition of UML drawing tool includes two parts: UML semantics and UML representation.

(1) UML semantic description is based on the precise metamodel definition of UML drawing tool. The metamodel provides a simple, consistent and universal definition for all elements of UML in syntax and semantics, enabling developers to be consistent in semantics and eliminating the impact of person-to-person expressions. In addition, UML supports extended definitions of metamodels.

(2) UML representation defines the symbol representation of UML drawing tools, which provides a standard for developers or development tools to use these graphical symbols and text syntax for system modeling. These graphic symbols and words express the application-level model, and semantically it is an example of the UML metamodel.

The important elements of the UML drawing tool can be defined by the following five types of diagrams (a total of 9 graphics):

The ◆ * * class is a use case diagram that describes the function of the system from the user's point of view and indicates the operator of each function.

The second type of ◆ is static diagrams (Staticdiagram), including class diagrams, object diagrams, and package diagrams. The class diagram describes the static structure of the class in the system. Not only define the classes in the system, represent the relationships between classes, such as association, dependency, aggregation, etc., but also include the internal structure of the class (class properties and operations). The class diagram describes a static relationship that is valid throughout the life cycle of the system.

An object diagram in the UML drawing tool is an instance of a class diagram, using almost the same identity as the class diagram. The difference between them is that the object graph shows multiple object instances of the class, not the actual class. An object diagram is an instance of a class diagram. Because the object has a life cycle, the object graph can only exist for a certain period of time in the system.

A package consists of packages or classes that represent the relationship between packages. The package diagram is used to describe the hierarchical structure of the system.

The third type of ◆ is behavior Graph (Behaviordiagram), which describes the dynamic model of the system and the interaction between the constituent objects. The state diagram describes all the possible states of the object of the class and the transition conditions of the state when the event occurs. In general, a state diagram is a supplement to a class diagram. In practice, it is not necessary to draw state diagrams for all classes, only for those classes that have multiple states whose behavior is affected by the external environment and changes.

The activity diagram describes the activities to be carried out to meet the requirements of the use case and the constraint relationship between the activities, which is helpful to identify parallel activities.

The fourth type of ◆ is the interaction diagram (Interactivediagram), which describes the interaction between objects. The sequence diagram shows the dynamic cooperative relationship between objects, which emphasizes the order of messages sent between objects and shows the interaction between objects at the same time; the cooperation diagram describes the cooperative relationship between objects, and the cooperation diagram is similar to the sequence diagram to show the dynamic cooperative relationship between objects. In addition to displaying the exchange of information, the collaboration graph also shows objects and their relationships. If you emphasize time and sequence, use the sequence diagram; if you emphasize the relationship between superiors and subordinates, select the cooperation diagram. These two kinds of graphs are called interactive graphs.

The fifth category of ◆ is the implementation diagram (Implementationdiagram). The component diagram describes the physical structure of the code components and the dependencies between the components. A part may be a resource code part, a binary part, or an executable part. It contains information about logical classes or implementation classes. Component diagrams help to analyze and understand the degree of interaction between components.

The configuration diagram in the UML drawing tool defines the physical architecture of software and hardware in the system. It can display the actual computers and devices (represented by nodes) and the connections between them, as well as the types of connections and dependencies between components. Within the node, executable components and objects are placed to display the correspondence between the node and the executable software unit.

From the perspective of application, when using object-oriented technology to design the system, the first step is to describe the requirements; secondly, to establish the static model of the system according to the requirements to construct the structure of the system; the third step is to describe the behavior of the system. The models established in steps * and step 2 are static, including use case diagrams, class diagrams (including packages), object diagrams, component diagrams and configuration diagrams, which are the static modeling mechanism of UML drawing tools. The model established in the third step can either be executed or represent the timing state or interaction at the time of execution. It includes four graphs: state diagram, activity diagram, sequence diagram and cooperation diagram. It is the dynamic modeling mechanism of UML drawing tool. Therefore, the main contents of UML drawing tools can also be classified into two categories: static modeling mechanism and dynamic modeling mechanism.

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